Photonic Crystal Multiple Diffraction Observed by Angular-Resolved Reflection Measurements

Angular-resolved reflection measurements suggest that higher-order Miller-index crystal planes of a fcc\ud photonic crystal reflect specularly about the normal to the\ud 111\ud planes. We suggest that this phenomenon\ud results from a two-step diffraction process where light is first Bragg diffracted by higher-order Miller-index\ud crystal planes and is then two-dimensionally diffracted by periodicities within the\ud 111\ud planes to produce the\ud specularly diffracted light. This phenomenon is a three-dimensional analog of the well-known Wood’s anomaly